To make such an attachment, for example to secure to the floor a rail element for longitudinal seat position adjustment, a means of attachment by screwing is commonly used, either by screwing a bolt into a nut joined to the floor, or screwing a nut onto a threaded stud joined to the said floor. Consequently, it is obligatory to perform a screwing operation when putting the seat in place in the vehicle, which is not always practical if the bolt heads or nuts are poorly accessible to conventional screwing tools.
In other cases, particularly when the connection of the seat to the floor must be readily separable, for example in the case of the rear attachments of seats with tilting seat pans, or with completely removable seats, it is known to make this attachment using different lockable anchoring systems, including hook systems or ball anchoring systems, which can be released relatively easily if necessary.
Generally speaking these systems are designed so that locking takes place automatically when the seat is brought into its utilization position. Unlocking is ensured by a control component such as a handle which can be pulled or turned to unlock the anchoring system. In many anchoring mechanisms, unlocking results in a more or less linear displacement of an actuator which releases the anchoring means, balls or hooks, allowing them to move in such a way that the anchoring component attached to the seat disengages from the anchoring component attached to the floor of the vehicle.
This actuator has two positions:                a locked position, which can only be obtained when the seat is anchored to the floor,        a released position, which is maintained as long as the seat is not anchored to the floor.        
The change from the released position to the locked position generally takes place automatically only when the seat is brought into the desired anchoring position on the floor. The change from the locked position to the released position requires intentional action by the user on the control component.
For information, the known ball anchoring systems generally comprise a tubular body with several radial holes in cut in the tube wall. A ball of diameter exceeding the wall thickness is placed in each hole. The actuator is a pin that slides within the tube and has a tapered section, level with the holes in the body, which pushes the balls outwards further to an axial movement of the pin. In the locked position, the tubular body attached to the seat is inserted into a hole of the corresponding diameter in the floor, and the pin is pushed downwards by a spring such that its tapered section forces the balls outwards causing them to protrude beyond the exterior of the tube, below the edge of the hole in the floor, thereby preventing withdrawal of the tubular body. To release the anchoring system, the pin must be pulled up against the force of the spring, by various control means, thus enabling the balls to move radially inwards into a retracted position with respect to the outer surface of the tubular body. The balls are held in this position by an outer sliding ring which covers them when the anchoring system is withdrawn from the hole in the floor. This means that the pin cannot return to its locking position as long as the said ring has not been pushed back by the floor when the tubular body is inserted into the hole in the floor, when the seat is put back into its utilization position. The position of the pin thus indicates whether the seat is locked or not. Further information on ball locking systems can be found for example in documents FR-2728317, FR-2735174, FR-2699973, FR-2771439.
As can be seen, such ball anchoring systems are relatively complex, requiring several components not only to ensure the actual locking action, but also to control release on demand and automatic relocking. They require the use of high-precision components to ensure reliability, therefore they are costly.
Other anchoring systems ensuring reliable but readily separable attachment of a seat to the floor are already known, such as known types of hook or cam anchoring systems, but they also feature numerous components, some of which are mobile or hinged with respect to the others to ensure the required functions of reliable locking and easy unlocking.
The use of these systems can therefore be justified for removable or at least tilting seats, where the attaching system must be readily released in order to maneuver the seat. But these systems are too sophisticated and therefore too costly for seats which are not intended to be removed or separated from the floor other than for exceptional maintenance operations.